Stenciling.



STATES TENT OFFTQJTI.

WILLIAM G. FUERTH, 0F NEWARK, NEW JERSEY, ASSIGNOR T0 EQUILIBRATOR COMPANY, OF NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY.

STENCILING.

No Drawing. Original application filed November 29, 1912, Serial No. 734,027.

tion filed April 21, 1917.

To all whom it may concern:

Be it known that 1, WILLIAM G. FUERTH, a citizen of the United States, residing in Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Stenciling, of which the following is a specification.

This invention relates to typewriter and other stencil sheets, and is a division of my application No. 753L027, filed November 29, 1912, Patent No. 1,238,906 of September 4, 1917.

One of the principal objects of the present invention is to provide for the softening or mollifying of a stencil sheet which is coated with a hardened gummy substance and which, in its original condition, is not suitable for being acted upon by'a stylus or by the types of the writing machine, without decreasing the fitness of the sheet for subsequent use in a stenciling machine or a duplicator.

Certain softening materials, such as glycerin for instance, if used upon a hardened gum coated sheet (gelatin or other gum) will render the coat permanently soft, whereas, according to one feature of the present improvements, the coatin is softened only temporarily and wil? harden again, so that its usefulness as a stencil sheet is not impaired by softening it preparatory to writing a stencil thereon.

Another feature of the invention is the use of an emollient for temporarily softening a stencil, which will have the effect of making the sheet even harder, tougher and more impermeable than before.

It has been proposed to use glycerin to soften the hardened coating of a Yoshino sheet, for the purpose of making a stencil (see U. S. patent to Zuccato, 54:8,116, British patent to Zuccato 12,136 of 189%, and other patents cited in my application hereinafter mentioned). But Where any gelatinous hardened coating is softened by such means, the coating is rendered permanently soft and objectionable. One of the features of my invention is a softener or emollient,

which will not only render the gelatinous coating soft for typewriting purposes, but

characteristics that it will make the stencil Patented Dec. 31, 1918.

Divided and this applica- Serial No. 163,759.

sheet harder, tougher, more durable and more impermeable than before. Furthermore, the new mixture may be used to harden a sheet upon which the stencil has already been written, even though the sheet may have been hardened previous to writing thereon, as for instance in treating a gummy sheet with formaldehyde.

One of the advantages of my invention is that a stencil made in accordance therewith is not liable to become punctured in running through the stenciling machine; and in fact by actual test more than one thousand stencil copies of the best character have been made from a single stencil without apparently wearing it out, the last copy appearing as good as the first, even though the stencil sheet had been taken out of the stenciling machine and washed several times.

Although the hard film or membrane is rendered soft for operating upon the same with the typewriter, still the re-agent Which does the softening contains a hardener to replace or restore the hard face or finish to the sheet, and render the stencil harder than it was before being softened.

I employ a stencil sheet consisting of Yoshino paper preferably coated with fishisinglass; the latter being prepared from fish bladder. The fish-isinglass is soaked in a little water, which is absorbed by the sub stance. and has the effect of making the substance easily soluble. Then the mixture thus partly prepared is placed in water and boiled until a thorough solution is made; the entire quantity of water used being about 40 parts by weight to one part of the fish-isinglass. (See my pending application No. 728,411). Preferably I use Russian fishisinglass because of its superiority for this purpose to the domestic isinglass, the latter being made partly from fish bladders and partly from other parts of fish. The coating so prepared is preferably applied to the .Yoshiuo sheet over a water bath.

This coating meets the peculiar requirements of filling up the pores of the Yoshmo sheet for the purpose of making a stencil sheet. The sheet so prepared is thin and extremely flexible, and not liable to crack, practically impermeable, and has great strength.

The durability of such stencil sheet may lars as to the process, construction, use, etc.

I employ an improved softener or emollient for this membranous stencil sheet, which enables the types to perforate the same, one of the results of the use of this softener being that when'the sheet dries, it

becomes harder and tougher than before it was softened, so that it becomes very durable and capable of stenciling an enormous number of copies and will withstand repeated washing, and rough handling, and

i otherwise substantially improved.

The emollient for use with the previously hardened stencil sheets, to soften them for use on the typewriter preferably comprises sulfonated castor oil (Turkey red oil) one part; chemically pure glycerin two parts; distilled water four parts; and formaldehyde (5% solution) one part; the liquid being flavored With essential oils, 9. s.

This mixture will temporarily soften the hardened coatings of paper or printing plates, so that they may be written upon by the typewriter or other means for making the stencils.

The foregoing mixture is extremely hygroscopic, which condition may be modified as desired, by reducing the proportion of glycerin, or varying the proportion of sulfonated oil. If a softening mixture is to be used for softening hardened sheets coated with ordinary animal gelatin, there should be an increase in the proportion of the sulfonated oil.

It will be understood that the fish-isinglass coatings require smaller proportions than animal gelatin coatings, of both sulfonated oil and glycerin in the emollient, because such sheets are relatively slow to dry or set.

The foregoing emollient is especially useful in softening coatings of paper which have been hardened or rendered insoluble, among which coatings may be enumerated those having various essential bases such as 'gelatins composed offarinaceous or vegetable or animal substances, and including soluble and insoluble albumen. The emollient is valuable when the coating consists of isinglass made from fish (acepinas). and

hardened; and is especially valuable where the sheet is coated with fish-isinglass made of the swimming bladder of the sturgeon.

The aforesaid emollient contains a hardening agent whose proportions may be varied according to the character of the coating of the stencil sheet which it is desired to soften. It will be understood that other hardening "agents than formaldehyde may be used, as, for instance, any of the re-agents well-known in the 'arts, such as bichromate of soda or of potash, hyposulfates, carbonates of ammonia, etc. different substances being best adapted to accord with the different bases of the stencil coating, to re-act for the purpose of again hardening, or increasing the hardness and toughness of the stencil coat or film or membrane which has been mollified by a mixture in accordance with my invention. It will be found that a the stencils will be rendered hard andimpermeable, and in most instances more concrete thanthey were prior to the mollification process.

The invention is not limited to the exact substances of. the foregoing formula, nor

do I desire it to be understood that the proten on the typewriter or by other means.

The invention is not limited to the exact" conditions above set forth, nor is it restricted in all cases to its use or application for'mollification purposes alone.

I have devised a method whereby the stencil sheet may be placed in the typewriter accompanied only by a hard backing sheet, and without the necessity of applying moisture to the stencil sheet on both sides.

I employ a backing of hard-faced paper such as Fourdrinie'r or rope manila, or wood paper, and such paper ll coat onone time needed while the stencil is being writside with a coating which may be composed of linseed oil, varnish or the like; the oil being heated to the burning point, and allowed to burn until it becomes ropy and tacky to such adegree as will permit grinding it in with any of the well-known unctuous earthy substances, such as kaolin, pumice, magnesium, umber, barium sulfate, or

the like.

After the earthy substance is incorporated with the oil, the same is applied to said backing sheet, to make it hard, stiff and practically impervious, so that the emollient or r ea res softening liquid may not be soaked up by the paper, thereby weakening the same, and so that the liquid may not be smeared over the typewriting machine. This coating is itself absorbent. If desired, the backing sheet may be tinted or colored for convenience in reading the typewritten stencil; and any of the well-known colors or pigments, as well as carbon or lamp black, may be ground in with the mixture.

After the backing sheet is coated and properly dried, it is rolled, calendered or smoothed, so as to present a dead face. The emollient is applied thereto with a brush.. The coating on the backing sheet will be found to be readily absorbent, and will retain for a long time upon its surface suliicient moisture or emollient to soften the stencil sheet. The latter is laid upon the moistened backing, and becomes itself softened throughout. The liquid will be retained by the coating on the backing sheet forimany hours, so that there is ample time in which to write a stencil on the typewriter. The stencil sheet may be laid smoothly down on the moist backing sheet, and any wrinkles may be brushed out with the aid of the edge of a blotter or other means; and then the two sheets may be introduced into the typewriting machine for writing the stencil.

- The moistened coating on the backing insures a proper state of softness of the coating on the stencil sheet, so that the typewriting operation may proceed leisurely. @ne of the advantages of this method is that the stencil sheet, when removed from the backing, does not retain an excess of the emollient or moistening fluid, and may in fact, without waitin to become dried, be placed directly upon tie stenciling machine, so that the op eration of stenciling may begin without loss of time. Said backing is of value in producing -a perfect stencil upon the typewriter, and it is found that even a Worn typewriter will produce acceptable results.

The herein-described stencil sheet, when used in connection with the described backing and moistened as aforesaid, will be found useful not only for making typewriter stencils, but also for making longhand stencils by means of a stylus. The stencil sheet may be very freely written upon, and of course will have the advantags that the writing will-be perfectly legible as it proceeds, as the dyed coating hereinafter referred to, Will be scored or pressed aside by the stylus, so that the light-colored backing can be seen where the stylus has written or marked. The earthy or powdery substance in the coating which is on the backing tends to make the same a little rough, and to that extent coiiperates with the stylus in displacing the coating on the on the sheet.

stencil sheet. Not only may writing be done, but lines can be easily ruled upon the stencil by means of the stylus. Forms may be ruled, and blanks therein filled up with writing by means of the stylus, or a form maybe ruled by the stylus, and the sheets may be inserted in the typewriter to fill up the blanks by use of the writing machine. The file plate or the like,which has heretofore been found necessary in preparing Wax stencils by means; of a stylus, may be dispensed with. A letter may be typewritten on the stencil, and the sheets removed from the typewriter, and the signature may be written at once upon the stencil by means of a stylus. The fibers of the sheet remain strengthened by the process of making it into a stencil sheet, so that it is practical to make a stencil Without tearing the paper, even though the coating is temporarily softened as aforesaid.

It will be seen that an open porous sheet, such as Yoshino, (or bolting cloth in some cases), is filled or coated with a solution of a concrete substance of fish (ichthyocollis) or animal matter, or .both,-such coating being incorporated with an astringent to render it hard and impermeable, producing (in the case of fish substance) a flexible parchment or membraniform stencil sheet or printing plate; the coating being of such con sistency when oiled or moistened or softened with an emollient, as to permit its being pressed aside to expose the pores of the sheet by means of a stylus or typewriting machine, for stenciling purposes, without cutting, lacerating or abrading the fibral construction of the sheet or removing or extracting any of the coating; said coating being capable of being re-hardened after the making of the stencil, by means of an astringent incorporated with the emollient, so as to reinforce and replace the hard face of the stencil sheet and correct any impairment of the same during the operation of preparing the stencil.

The emulsion may be termedv a saponaceous emollient with an astringent, and it works upon a membrane, consisting preferably of Yoshino coated with fish-isinglass and hardened at the time of manufacture in the manner set forth in my said application No. 728,411. The. emollientas a result of having both oily and saponaceous qualities, appears to have a decided lubricating edect The coating on the Yoshino sheet is a membranous coating, which is softened by the emollient, and the astringent in the emollient emulsion finally closes up the fine pores, to make the same impervious to the stenciling ink, or substantially so.

Although the emollient contains glycerin and oil, nevertheless, owing to the use of the formaldehyde therewith, the stencil sheet becomes stronger and better than before using the emollient. The formaldehyde solution or other astringent or hardening agent may be appliedif desired without the castor oil or the glycerin, merely for hardening and toughening the sheet after the stencil is written. v

This emollient can be applied to either of the before-described sheets, one of which consists of a Yoshino sheet coated with fishisinglass, while the other is of harder and tougher texture, owing to the original hardening treatment thereof by formaldehyde or other substances. My emollient is not limited in all cases to the use of the exact stencitsheetsdescribed in said application N 0. 728,411.

Yoshino paper has never been deemed suitable for autographic stencil work, because of the liability cf'the sharp-pointed writing instrument catching in the fibers and tearing the same; so that it has been the practice to employ a closely-woven tissue sheet as a base for a wax or parafiin stencil sheet for autographic purposes. But a Yoshino sheet may be coated with fish-isinglass (or in some cases with other gummy substance) and subsequently coated on one side with wax, and then the gum-coating can be softened, and the whole will be found suitable for autographic purposes. The stylus does not tear v this sheet. The fiber i's so strengthened by fish-isinglass, (especially if a hardening agent is originally used,) that there is no liability of the point of the stylus tearing the same. The Wax used for this purpose should be of a very hard variety.

Preferably for ordinary work the coating composition comprising fish-isinglass, glycerin and water, is colored by means of a dye, as, for instance, negrosin, which makes the stencil sheet itself black or of a dark hue. A stencil may be laid upon the herein-described backing containing the unctuous earthy substance and dampened by the emollient, the backing sheet with its coating of earthy substance being light colored, and when the stencil is written in a typewriter, the types in pressing aside the coating, will make the sheet transpicuous, and the light colored backing will make the typewriting appear in light letters on the dark stencil sheet. Moreover, when the stencil is removed from the backing, it can also be easily read.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

ing formed of hard-faced paper such as.

Fourdrinier or rope manila, and coated with a coating of linseed oil with which is incorporated an unctuous earthy substance.

2. A backing for a stencil sheet, said backing formed of hard-faced paper such as Fourdrinier or rope manila, and coated with a coating of linseed'oil with which is incorporated an unctuous earthy substance, and pigment.

3. A backing for a stencil sheet, said backing formed of hard-faced paper such as Fourdrinier or rope manila, and coated with a coating of linseed oil with which is incorporated an unctuous earthy substance, and pigment, and treated with an emulsion of sulfonated castor oil, glycerin, water and formaldehyde.

4. A backing for a stencil sheet, said back ing' formed of hard-faced paper such as Fourdrinier or rope manila, and coated with a coating of linseed oil with which is incorporated an unctuous earthy'substance, and pigment, and treatedwith an emulsion of sulfonated castor oil, glycerin, water and. formaldehyde; the .stencil. sheet being attached at one end to the backing sheet.

5. A process in making a stencil copy, comprising coating a Yoshino sheet with fish-isinglass, hardening the coated sheet by means of a hardening agent, coating a sheet with a compound of oil and unctuous earthy substance to form a backing for the Yoshino sheet, rolling or smoothing the backing sheet, applying thereto an emollient comprising sulfonated castor oil, glycerin, water and formaldehyde, placing thereon said coated Yoshino sheet to be softened thereby, and introducing the superposed sheets into a typewriter to write the stencil thereon from which to produce such copy.

6. A backing sheet for the purpose specified, comprising hard-faced paper coated with a composition of linseed oil or varnish, with which is ground an unctuous earthy substance.

7. A backing sheet'for the purpose speci fied, comprising hard-faced paper coated with a'composition of linseed oil or varnish,

with which is ground an unctuous earthy 

